Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates generally to a system, apparatus and method for mixing and dispensing foams and, more particularly, to a system, apparatus and method for mixing and dispensing expanding foams employing an adjustable orifice flow regulating device for controlling the composition of the resulting foam.
2. Description of the Related Art
Various foam dispensing systems and apparatuses, including guns, have been proposed and used for mixing and dispensing synthetic foams, including such expanding synthetic foams as polyurethane or polyisocyanurate foams. Typically, preparation of an expanding synthetic foam requires the uniform mixing of two fluid components. For example, in a polyurethane foam, one component is a polyol component, referred to as the B component, and the other component is an isocyanate component, referred to as the A component. The A and B components may include one or more other agents, including, but not limited to, foaming agents, curing agents, catalysts or accelerators. The A and B components are conventionally stored in separate containers prior to use. Typically, the two components are combined in the mixing chamber of a dispensing apparatus or dispensing gun to create the expanding foam. When the two components are mixed in proper proportions, they typically react quickly to form and solidify into the expanding foam.
Current methods of regulating the ratio of these streams leverage the control of the viscosity of the chemicals and/or the pressure of each component stream. Controlling the viscosity of the chemical components typically requires the application of heat. Such a method of stream control is generally undesirable due to its cost. Controlling component streams with pressure has its own problems in that to change the pressure of the chemical components in a conventional system, the operator must take the gun back to the area where the chemical tanks and the pressure controls are located to make adjustments to the pressures and flow rates of the chemicals. In order to make these adjustments, each of the chemical vessels connected to the dispensing gun commonly employ separate pressure controls so that their respective pressures may be independently adjusted.
It is desirable to be able to regulate the ratio of the chemical component streams of a foam component mixing apparatus quickly and easily. It is also desirable to be able to regulate the ratio of the chemical components at the dispensing apparatus. It is also desirable to be able to vary the throughput of the dispensing apparatus at the apparatus.
The present invention includes a method, apparatus and system for mixing and dispensing chemical component streams of a foam component wherein regulating the ratio of the chemical component streams is quick and easy and controlled at the dispensing apparatus. Additionally, the present invention allows the operator to control the throughput at the dispensing apparatus.
The dispensing system for mixing first and second components and dispensing an expanding foam preferably includes separate vessels containing each foam component and a dispensing apparatus. The dispensing apparatus preferably includes a cartridge assembly mounted on a body assembly. The cartridge assembly further preferably includes a mix chamber and first and second ports, each port for supplying a foam component to the mix chamber. A pair of adjusting valves is also preferably mounted to the cartridge assembly with each adjusting valve operable to individually adjust the flow of each foam component to the mix chamber. A pair of hoses preferably connects the component vessels to the cartridge assembly. Each adjusting valve preferably includes a variable orifice device in the cartridge assembly operable to vary the flow area of the port. The present invention further includes a method for adjustably controlling, at the dispensing apparatus, the flow of each of the first and second foam components to the mixing chamber such that the ratio of the foam components therein may be easily altered and controlled.